NHBE cells were transfected with a variety of different oncogenes: raf, v-Ha-ras, a combination of raf and v-myc on the same plasmid and the translocated c-myc frame of the CA46 Burkitt's lymphoma (BL) cell line. The transfected cells were then selected for resistance to inducers of differentiation by treating them with blood-derived serum (BDS) or TPA. The CA46 translocated c-myc gene was the most effective oncogene in inducing resistance to differentiation in normal human bronchial epithelial (NHBE) cells. The translocated c-myc gene has been further analyzed by testing deletion mutants of the original clone for resistance to differentiation and induction of transformation in both biological assay systems.